More particularly, the embodiments of the present invention relates to a writing instrument comprising a barrel extending along a longitudinal axis, a cartridge housed inside the barrel and having a front end connected to a writing point and a rear end, and a cartridge support connected to the barrel and against which the rear end of the cartridge rests.
In the prior art there are supports of this sort that have a planar base approximately perpendicular to the longitudinal axis and against which the rear end of the cartridge rests. These supports have the advantage of being easy to produce and of requiring little plastics material. However, with these supports the rear end of the cartridge is not immobilized, which can have a detrimental effect on the operation of the writing-point extension and retraction mechanism and can result in clicking noises which give the user a poor impression of the quality of the instrument.
Other supports have a housing in the form of a cylindrical well in which the rear end of the cartridge is inserted more or less tightly. These supports have however the defect of being suitable for cartridges where the rear end is of an approximately constant diameter, which creates problems when it is wished to use this support with cartridges of a slightly different shape. Moreover, this kind of support requires more complex molds to form both the side walls of the support and the hollow housing into which the cartridge is inserted.